Method of manufacturing a thermally conductive circuit board with a ground pattern connected to a heat sink

Inactive Publication Date: 2005-03-01
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

According to the present invention, a ground connection portion can be provided in a desired position in a wiring pattern of a board including a sheet-like thermally conductive resin composition containing an inorganic filler added to a thermosetting resin composition at a high ratio, an electrically conductive heat sink, and a lead frame as the wiring pattern. Therefore, the degree of freedom in design is improved and a grounding pattern can be provided during the production of the board. Furthermore, since the ground connection outside the board is not required, the size of the board can be reduced. As a result, the grounding pattern and the heat sink can be connected electrically with each other in an arbitrary place inside the insulating layer of the thermally con

Problems solved by technology

Accordingly, the insulated metal substrate has a problem in that a portion between the circuit pattern and the metal plate as a ground tends to be affected by noise easily,

Method used

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  • Method of manufacturing a thermally conductive circuit board with a ground pattern connected to a heat sink
  • Method of manufacturing a thermally conductive circuit board with a ground pattern connected to a heat sink
  • Method of manufacturing a thermally conductive circuit board with a ground pattern connected to a heat sink

Examples

Experimental program
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Effect test

Example

Example 1

In order to produce a sheet-like thermally conductive resin composition used in the present invention, an inorganic filler and a thermosetting resin composition were mixed and processed in a slurry form. The composition of the thermally conductive resin composition thus obtained is described as follows.(1) Inorganic filler: 89 wt. % Al2O3 (AS-40, with a mean grain size of 12 μm, manufactured by Showa Denko Co., Ltd.)(2) Thermosetting resin: 10 wt. % brominated polyfunctional epoxy resin (NVR-1010, containing a curing agent, manufactured by Japan REC Co., Ltd.)(3) Other additives: 0.5 wt. % curing accelerator (imidazole, manufactured by Japan REC Co., Ltd.), 0.4 wt. % carbon black (manufactured by Toyo-Carbon Co., Ltd.), and 0.55 wt. % coupling agent (Preneact KR-46B, manufactured by Ajinomoto Co., Inc.)

Methyl ethyl ketone (MEK) was added to those materials as a solvent and further alumina balls were added thereto. They were mixed using a ball mill at 800 rpm for 40 hours. T...

Example

Example 2

The following description is directed to an example of a thermally conductive board in which the surface of a metal pole inserted in a heat sink is used as a grounding pattern.

A sheet-like thermally conductive resin composition and a lead frame produced by the same methods as in Example 1 were prepared. In addition, a 3-mm thick aluminum sheet was prepared and a recessed portion with a 2 mm×2 mm square shape and a depth of 1.5 mm was provided in a part of the aluminum sheet. An aluminum metal pole having a length of 3 mm with a two step protrusion at its one end was prepared. The protrusion had a length of 1.5 mm. The flat surface of the metal pole on which the protrusion was not formed was solder-plated. Next, the two step protrusion (2.05 mm×2.05 mm square) of the metal pole was fitted into the recessed portion of the aluminum sheet. Thus, a heat sink with a metal pole as shown in FIG. 2A was produced.

The heat sink with a metal pole, the lead frame, and the sheet-like the...

Example

Example 3

The following description is directed to an example of a thermally conductive board in which a desired portion of a heat sink was extruded to be processed in a protrusion form and a grounding pattern is connected to the heat sink using the protrusion.

A sheet-like thermally conductive resin composition was produced by the same method as in Example 1. The composition of this thermally conductive resin composition is described as follows.(1) Inorganic filler: 90 wt. % Al2O3 (AS-40, with a mean grain size of 12 μm, manufactured by Showa Denko Co., Ltd.)(2) Thermosetting resin: 9 wt. % cyanate ester resin (“AroCy M30”, manufactured by Asahi Ciba Co., Ltd.)(3) Other additives: 0.4 wt. % carbon black (manufactured by Toyo-Carbon Co., Ltd.), 0.2 wt. % dispersant (“PLYSURF, A-208F”, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 0.4 wt. % silane coupling agent (A-187, manufactured by Nippon Unicar Co., Ltd.)

Next, a circuit pattern was formed by punching in a 42-alloy (an allo...

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Abstract

In a method of manufacturing a thermally conductive circuit board with high heat dissipation, high conductivity and high ground-connection, a sheet-like thermally conductive resin composition containing 70 to 95 wt. % inorganic filler and 5 to 30 wt. % thermosetting resin composition, a lead frame as a wiring pattern, and an electrically conductive heat sink with a metal pole placed therein are superposed, heated and compressed, and thus are combined to form one body. Consequently, a thermally conductive circuit board with a flat surface is obtained in which a grounding pattern is grounded to the heat sink inside the insulating layer. Thus, the grounding pattern and the heat sink can be connected electrically with each other in an arbitrary position inside the insulating layer of the thermally conductive circuit board. The method provides that a part of a lead frame and heat sink are connected not only mechanically, but also electrically, and allows an associated power module size to be reduced and its density to be increased.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates generally to a circuit board on which various semiconductor devices or electronic components are to be mounted. Particularly, the present invention relates to a resin board (a thermally conductive board) with high heat dissipation that is suitable for use in the power electronics field and to a power module including the same.2. Related Background ArtRecently, there have been demands for increases in density and improvements in function of semiconductors, as a higher performance and a smaller size are required in electronic equipment. Accordingly, smaller higher-density circuit boards on which such semiconductors are to be mounted also have been required. Hence, a design with consideration to heat dissipation of a circuit board has become important. As a technique of improving heat dissipation of a circuit board, a method employing an insulated metal substrate using a metal plate made of, for example, ...

Claims

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Application Information

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IPC IPC(8): H01L23/373H01L23/498H01L23/433H01L23/48H01L23/34H05K7/20H05K1/02H05K1/05H05K3/40H05K3/20B29C43/18C08K3/00C08J5/18C08L101/00H01L23/50H05K1/03
CPCH01L23/3737H01L23/49861H05K1/0204H05K1/056H05K7/20463H05K7/205H01L23/4334Y10T29/49121H01L2224/48247H01L2924/01046H01L2924/01078H01L2924/01079H01L2924/19041H05K3/0061H05K3/202H05K3/4084H05K2201/0209H05K2201/0382H05K2201/09054H05K2201/0969H05K2201/10416H05K2203/1189H01L24/48H01L2924/01019H01L2924/01322H01L2924/13055Y10T29/49171Y10T29/49158Y10T29/49146H01L2924/1305Y10T29/49172Y10T29/4913H01L2924/00H01L2224/451H01L2924/00014H01L24/45H01L2224/05599
Inventor HIRANO, KOICHINAKATANI, SEIICHIMATSUO, MITSUHIROYAMASHITA, YOSHIHISA
Owner PANASONIC CORP
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